Occlusion, temporomandibular disorders, and orofacial pain: An evidence-based overview and update with recommendations

Occlusal considerations in maintaining health of implants and their restorations

Dental implants are a regular feature in daily clinical practice and there is a need to undertake routine assessment and maintenance of implants and their restorations on par with that provided for natural teeth. Occlusal checks form an important part of the maintenance regime for preserving the integrity of implants, their restorations, and health of the peri-implant tissues. Implant restorations are subjected to the full characteristics and magnitude of occlusal forces, including those associated with parafunction. Compared with the periodontal ligament around teeth, the biophysical response to occlusal forces of osseointegration is different through the more rigid link of implant to bone and reduced proprioception. Risks attributable to occlusal forces primarily affect implant restorations and they are elevated in the presence of bruxism. The occlusal guidelines recommended by the literature are aimed at reducing these risks and regular assessment and maintenance of the occlusion is essential. A four-step sequence is presented to ensure that the annual occlusal checks include the patient's input and evaluation of restoration integrity, occlusal scheme, additional protection, and spatial changes.

Investigation of the accuracy of dynamic condylar position: A model study

OBJECTIVES

To evaluate dynamic condylar positions by integrating mandibular movement recording data and cone-beam computed tomography (CBCT) and to investigate its accuracy via dynamic model experiments.

METHODS

A polyvinyl chloride skull model was utilized. A robot arm was used to operate the mandible to perform mouth opening, closing, protrusion, and lateral movements. A recording device, worn on the skull, was used to record the dynamic process and an optical position tracking (OPT) system was used to simultaneously trace the movements. A self-developed software module was used to evaluate the dynamic condylar position by integrating the dynamic tracing data and a virtual skull model derived from CBCT images. Errors were defined as differences between the dynamic coordinates of six landmarks around the condylar area derived from the software module (test) and OPT system (gold standard).

RESULTS

The condylar position errors were 0.76 ± 0.31, 0.55 ± 0.15, and 0.68 ± 0.23 mm for mouth opening, bilateral, and protrusion movements, respectively. Furthermore, the errors for small, moderate, and large mouth opening movements were 0.62 ± 0.19, 0.69 ± 0.29, and 0.94 ± 0.31 mm, respectively. The errors for all movements, except for large mouth opening, were significantly less than 1 mm (P < 0.05). The error was not different from 1 mm in the large mouth opening movement (P > 0.05).

CONCLUSIONS

Our developed method of achieving dynamic condylar position by integrating mandibular movement recording data and CBCT images is clinically reliable.

CLINICAL SIGNIFICANCE

This study proved the reliability of evaluating dynamic condylar position using a commercial dynamic recording instrument and CBCT images.

Do dental implant therapies arouse signs and symptoms of temporomandibular disorders? A scoping review

OBJECTIVE

To delineate and discuss the literature about TMD in the context of dental implantology.

METHODS

The PRISMA-ScR and Joanna Briggs guidelines for scoping reviews were used as methodological parameters. In vivo studies published in the English language showing interplay between dental implant therapy and TMD were included. A systematic screen strategy was applied in two platforms to obtain a broad range of relevant literature published in English.

RESULTS

The literature review indicated that prolonged surgical procedure may be a risk for TMD. Conversely, implant-supported prostheses were found to contribute to the mitigation of some TMD aspects. Empirical principles for the best practice in implant dentistry concerning the TMD were discussed in the present study.

CONCLUSION

The included clinical studies suggest that factors associated with the implant placement, such as long duration of surgical procedures, may represent risk factors for TMD. They also indicate long-term benefits of implant-supported restorations.

What are the best parameters of low-level laser therapy to reduce pain intensity and improve mandibular function in orofacial pain? A systematic review and meta-analysis

PURPOSE

To determine the effectiveness of laser therapy for managing patients with orofacial pain (OFP). In addition, to determine which parameters provide the best treatment effects to reduce pain, improve function, and quality of life in adults with OFP.

METHODS

Systematic review. Searches were conducted in six databases; no date or language restrictions were applied. Studies involving adults with OFP treated with laser therapy were included. The risk of bias (RoB) was performed with the Revised Cochrane RoB-2. A meta-analysis was structured around the OFP type, and outcomes. Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) assessed the overall certainty of the evidence.

RESULTS

Eighty-nine studies were included. Most studies (n = 72, 80.9%) were considered to have a high RoB. The results showed that laser therapy was better than placebo in improving pain, maximal mouth open (MMO), protrusion, and tenderness at the final assessment, but with a low or moderate level of evidence. The best lasers and parameters to reduce pain are diode or gallium-aluminum-arsenide (GaAlAs) lasers, a wavelength of 400-800 or 800-1500 nm, and dosage of <25 J/cm2.

CONCLUSIONS

Laser therapy was better than placebo to improve pain, MMO, protrusion, and tenderness. Also, it was better than occlusal splint to improve pain, but not better than TENS and medication.Implications for rehabilitationLaser therapy was found to be good in improving pain, maximal mouth opening, jaw protrusion, and tenderness at the end of the treatment.For patients with all types of temporomandibular disorders (TMDs) (myogenous, arthrogenous, and mixed), the following lasers and parameters are recommended: diode or gallium-aluminum-arsenide (GaAlAs) laser, wavelength of 400-800 or 800-1500 nm, and a dosage <25 J/cm2.For patients with arthrogenous TMDs, the following lasers and parameters are recommended: Diode laser and a wavelength between 400 and 800 nm.For patients with myogenous TMDs, the following lasers and parameters are recommended: diode laser, wavelength between 800 and 1500 nm, and dosage of <25 J/cm2.For patients with mixed TMDs, the following lasers and parameters are recommended: diode, GaAlAs, or infrared laser, a wavelength of 800-1500 nm, a dosage >100 J/cm2, and an application time between 15 and 30 s or >60 seconds.

Classifying Temporomandibular Disorder with Artificial Intelligent Architecture Using Magnetic Resonance Imaging

This study proposes a new diagnostic tool for automatically extracting discriminative features and detecting temporomandibular joint disc displacement (TMJDD) accurately with artificial intelligence. We analyzed the structural magnetic resonance imaging (MRI) images of 52 patients with TMJDD and 32 healthy controls. The data were split into training and test sets, and only the training sets were used for model construction. U-net was trained with 100 sagittal MRI images of the TMJ to detect the joint cavity between the temporal bone and the mandibular condyle, which was used as the region of interest, and classify the images into binary categories using four convolutional neural networks: InceptionResNetV2, InceptionV3, DenseNet169, and VGG16. The best models were InceptionV3 and DenseNet169; the results of InceptionV3 for recall, precision, accuracy, and F1 score were 1, 0.81, 0.85, and 0.9, respectively, and the corresponding results of DenseNet169 were 0.92, 0.86, 0.85, and 0.89, respectively. Automated detection of TMJDD from sagittal MRI images is a promising technique that involves using deep learning neural networks. It can be used to support clinicians in diagnosing patients as having TMJDD.

Cannabis Bioactive Compound-Based Formulations: New Perspectives for the Management of Orofacial Pain

The management of orofacial pain to alleviate the quality of life of affected patients is becoming increasingly challenging for scientific research and healthcare professionals. From this perspective, in addition to conventional therapies, new alternatives are being sought, increasingly looking at the use of both natural and synthetic products. Cannabis sativa L. represents an interesting source of bioactive compounds, including non-psychoactive cannabinoids, flavonoids, and terpenes, many of which are effective in improving pain intensity. Here, we aim to analyze the possible mechanisms of action of the bioactive natural and synthetic hemp-derived compounds responsible for the modulatory effects on pain-related pathways. The ability of these compounds to act on multiple mechanisms through a synergistic effect, reducing both the release of inflammatory mediators and regulating the response of the endocannabinoid system, makes them interesting agents for alternative formulations to be used in orofacial pain.

Prosthodontic Treatment in Patients with Temporomandibular Disorders and Orofacial Pain and/or Bruxism: A Review of the Literature

Temporomandibular disorders are a group of conditions affecting the temporomandibular joints, the jaw muscles, and related structures. Patients with temporomandibular signs and/or symptoms frequently present with indications for prosthetic treatment. The management of these patients aims to achieve patient comfort, occlusal stability, and the complex restoration of the teeth. The goal of this review is to provide an overview of the relationship between prosthodontics and temporomandibular disorders and/or bruxism with a focus on the cause-and-effect implications and the strategies for planning prosthetic treatments in patients with temporomandibular disorders and/or bruxism.

A 10-year overview of chronic orofacial pain in patients at an oral medicine center in Iran

Background

Orofacial pain is defined as pain felt in the soft or hard tissues of the head, face, mouth, and neck. Chronic orofacial pain is often challenging to diagnose and difficult to treat. Due to the lack of available information about the prevalence and clinical form of orofacial pain, this study aimed to evaluate the characteristics of chronic orofacial pain in patients presenting at the Department of Oral Medicine of Shahid Beheshti Dental School between 2012 and 2022.

Methods

In this retrospective study, we evaluated the files of 121 patients at the Department of Oral and Maxillofacial Diseases of Shahid Beheshti Dental School, which were completed during 2012–2022. We extracted the required information from these files.

Results

In total, 121 files were included in the study (30 male, 91 female). The mean age of the patients was 43.68 ± 16.79 years. The most common diagnosis in patients with chronic orofacial pain was temporomandibular disorders (TMD) (55.3%). Among pain-related factors, psychological factors showed the highest frequency (30.5%). Opening and closing (43.8%) had the highest frequency among factors that increased pain, and the rest (6.6%) had the highest frequency among the factors that reduced pain. Most patients experienced unilateral pain over the masseter area. Most patients reported their pain intensity to be greater than 7 in the verbal analog scale (VAS). The most common symptom associated with pain was joint noise (37.1%).

Conclusion

A ten-year retrospective evaluation of patient files showed that more than half of the patients with chronic orofacial pain had TMD.

Occlusal Indicators Used in Dental Practice: A Survey Study

Introduction

The function of the masticatory apparatus is complete when the dentition is intact with contact between the individual teeth and proper occlusion with the antagonists. For years, occlusal contacts have been studied to determine their exact location and describing various materials and methods for their registration such as paper foil, silk, and Shimstock foil. For years, occlusal contacts have been studied to determine their exact location and describe various materials and methods for their registration such as paper foil, silk, shim stock foil, the T-Scan system, and more recently the OccluSense system. The primary aim of the study was at evaluating which of the occlusal indicators is the most commonly used in practice, and the secondary aim was whether dentists are willing to use digital methods to examine occlusion.

Materials and Methods

The main primary information of the survey was collected by sending electronically anonymous questionnaires to 2014 dentists, randomly selected from all regions of the country. 228 questionnaires were filled in and returned. To achieve the goal of the study, the self-developed questionnaire was created and tested to survey the opinion about the use of occlusal indicators in dental practice. Each questionnaire contains questions about the sociodemographic and professional status of the people in the group and their opinion about the positives and negatives and the effectiveness of occlusal indicators.

Results

The obtained results confirm the statement that the most frequently used occlusal indicator in dental practice is the articulation paper. Articulation foil and silk are used less frequently than articulation paper. Of the listed quality indicators, Shimstock foil is rarely used in practice. Of the indicated quantitative indicators, the T-Scan system is more used than the OccluSense system. In the era of rapid technology development, the opinion and desire of dentists to increasingly want to introduce in their clinical practice quantitative methods are the digital diagnosis of occlusion.

Conclusion

In any dental practice, if technically possible, digital methods would be used, giving more accurate and reliable data on the registered occlusal contacts.

Occlusal Trauma Induces Neuroimmune Crosstalk for a Pain State

Temporomandibular joint (TMJ) disorder caused by occlusal trauma is one of the most controversial topics in dentistry. Experimental traumatic occlusion (ETO) induced by metal crowns cemented to mandibular first molars in rats causes a long-lasting nociceptive response. This study aimed to elucidate whether ETO generates an increase in inflammatory mediators in the TMJ. In addition, the impact of ETO on trigeminal ganglia, neurotransmitter release, and satellite glial cell (SGC) activation was investigated. ELISA revealed enhanced inflammatory mediators, including TNF-α, IL-1β, IL-6, CX3CL1, and ADAM-17 by Western blotting, in periarticular TMJ tissue after 28 d of ETO. In the trigeminal ganglia, ETO groups increased the release of the neurotransmitters substance P and glutamate. Overexpression of the AMPA receptor and upregulation of NMDA were observed in the 0.4- and 0.7-mm ETO groups, respectively, highlighting enhanced neuronal excitation. Increased IL-1β and COX-2 mRNA levels in the 0.7-mm ETO group confirmed trigeminal ganglia SGC activation. Immunofluorescence and electrophoresis of SGC revealed increased pERK expression in the 0.7-mm ETO group. ERK phosphorylation was shown to be nociceptive specific, with its upregulation occurring in cases of chronic inflammatory pain. Increased PKA mRNA levels were observed in the 0.4-mm ETO group, while CREB mRNA levels were upregulated for both ETO groups. Electrophoresis showed overexpression of sodium channel Nav 1.7 in the 0.7-mm ETO group, while immunofluorescence revealed that Nav 1.7 is expressed in sensory trigeminal ganglia cells. The results of this study suggest that occlusal trauma induces neuroimmune crosstalk, with synthesis of proinflammatory/pronociceptive mediators, which increases neuronal activity in trigeminal ganglia via the activation of an inflammatory response cascade to develop a persistent neuroinflammatory state that leads to central sensitization.

Coronal Restorations and Temporomandibular Joint (TMJ) Dysfunction: A Survey Among General Practitioners of the Town of Abidjan

Background:

The paper surveyed the knowledge of general practitioners to coronal restorations and temporomandibular dysfunction. The specific aim of this study was to evaluate the knowledge and therapeutic approaches of the general practitioners in terms of restoring occlusion, aesthetics and function after restorative treatments in other to make recommendations to prevent potential dysfunction of the temporomandibular joint.

Methodology:

A cross sectional descriptive survey was used. It was carried out on 86 dentists out of the entire population size of 152 dentists practicing within Abidjan’s center municipality, randomly selected from the database provided by the National College of Dental Surgeons of Ivory Coast. A structured questionnaire was administered to collect data, which was subsequently collated and analysed.

Results:

The majority of the practitioners (95.4%) knew how to diagnose TMJ dysfunction. The etiological factors were stress for 55.2% of the practitioners and amalgam overhang for 49.4% of them. The precautions used to avoid TMJ disorders consisted of good control of the occlusion after having performed a restoration (55%) and taking into account the occlusal morphology (32%) at the time of shaping. Fifty-four percent of the practitioners systematically reevaluated the restorations undertaken.

Conclusion:

Impairment of occlusion results in improper muscular responses and leads to changes in pressure at the level of the temporomandibular joint. This study revealed that the general practitioners of the town of Abidjan have a good level of knowledge of the consequences of poorly carried out restorations on the initiation of masticatory apparatus disorders.